Machine for grinding worms and the like



W. CANNELL.

MACHINE FOR GRINDI NG WORMS AND THE LIKE. APPLICATION mu) oms, 19'14.

1,346, 1 73 Patented July 13, 1920.

4 SHEEISSHEEI 1'.

Tgz.

' Il/EMTOR W. CANNELL.

MACHINE FOR GRINDING WORMS AND THE LIKE.

a) Wm APPLICATION FILED DEC.8, I914. LQAQJ Us 4 SHEETS-SHEET 2 ym/(LA, WQ 4 We %4 Tram/H Patented July 13, 1928.,

AW. CANNELLa MACHINE FOR GRINDING worms AND THE LIKE.

APPLICATION FILED DEC-8| 1914. 1 346 173 Patented July 13, 1920c 4 SHEEIS-SHEEI 3.

I A E W. CANNELL.

MACHINE FOR GRINDING WORMS AND THE LlKE.

APPLICATION FILED DEC-8,1914.

Patented July 13, 1920.

4 SHEISSHEEI 4.

f) q WITNES 8 4 d/7/7@//, INVENTOR hit STATES PATET OFFICE.

MACHINE TOOL COMP A CORPORATION OF MASSACHUSETTS.

MACHINE FOR. GRINDING WOBMS AND THE .LIKE.

intents.

Specification of Letters Patent.

Patented July 13, 1920..

Application filed December 8, 1914. Serial No. 876,039.

To all whom it may concern;

Be it known that 1, WILLIAM CAi INELL, a subject of Great Britain, and a resldent of Springfield, Massachusetts, have invented certain new and useful Improvements in Machines for Grinding Worms and the like, of which the followingis a SPQCIfiCELtIOII.

This invention aims to provide a machine for grindingwith an emery or other abrading wheel, the'teeth of gears of all sorts and especially of worms and spiral gears. Special means are provided, in addition, for relieving, or slightly tapering, the ends of the teeth of a work-piece by means of the gr1nding wheel; or of guiding the grinding wheel so that it will grind the faces of teeth whlch have been formed with such a relief or taper at their ends. Gears generally, and especially worms, hobs and the like are OIdlnarily made of steel and after being cut to shape, are hardened by heat treatment. This treatment sometimes distorts the shape of the work so that its efliciency is greatly reduced. By subsequently grinding suc hardened pieces in the present machine they can be brought to perfect shape without injuring the temper of the steel, so as to be most efficient and durable.

The accompanying drawings illustrate a machine embodying the invention.

Figure l is 'a front elevation of the machine in the operation of grinding a worm; Fig. 2 is a side elevation of the same partly broken away;

Fig. 3 is a vertical section through the carrier for the grinding wheel on the line 3-3 of Fig.4;

Fig. 3 is an edge View of an alternative shape of grinding wheel; Fig. 4 is a plan of the head of the grmdin wheel carrier; 1

Fig. 5 is an end View of the sameon a plane normal to the axis of the grinding wheel, supposing the grinding wheel adiusted to brin its axis parallel to that of the carrier an to cause it to cut at a rlght angle to such axis;

Figs. 6 and 7 are respectivel a side elevation and a front elevation 0 a means for automatically producing teeth of 'special shape or grinding worms having teeth of special shape;

Fig. 8 is a plan of the equalizing lever of Figs. 6 and 7.

Referring to the embodiment of the invention illustrated the grinding wheel A has a tapered edge as shown in Fig. 3 to fit in the grooves between the teeth of the worm; or is made as at A in Fig. 3 to fit over the tapered teeth of the worm B. The worm is mounted between a head stock C and a tail stock D and is rotated slowly. At the same time the head E which carries the grinding wheel is rotated on its axis extending from front to rear through the machine, so that the combination of movements produces a relative spiral movement of the grinding wheel upon the worm, the pitch of the spiral depending upon the relative velocities of the two rotary movements referred to. The grinding wheel is set in an oblique plane (Fig. 4), corresponding to the pitch of the worm, and is rotated at a rapid rate on its spindle F so as to grind smooth the faces of the worm threads.

The spindle in the head stock C, by which the worm B isrotated, carries on its end a gear G which is driven from the gear H which is carried by a larger gear J which is driven through intermediate pinions K and L, the latter on a shaft M which runs through the machine from side to side and carries on its opposite end a cone pulley N by which is driven. The gears J, K and L are carried on a plate 0 which can be swung about the shaft M to permit a change in the ratio of the gearing between the shaft M and the spindle of the head stock C so as to rotate the worm l3 constituting the work faster or slower according to the pitch of its threads.

The shaft M also drives through beveled gears P and Q; a vertical shaft R splined near its upper end through a worm S which drives a worm gear T mounted on the barrel U of the carrier for the grinding. wheel. The carrier is by these means rotated at such a rate as to sweep the grinding wheel across the face ofone after another of the teeth of the worm B as the latter is rotated.

The-grinding wheel is rotated on its spindle F by means of a belt or pulley Vonthe rear end of a shaft W which (Fig. 3) extends through the barrel U and into the head of the carrier.

The head of the carrier comprises a to plate X fastened by means of a flange (Fig. 3) on the end of the barrel U, .a bottom plate Z projecting forward from the lower portion of the flange Y, and a central vertical pin a having its head located in an opening in the top plate'X and its lower end screwed into the forward portion of the bottom plate Z. The shaft W has keyed on its forward end a beveled pinion Z) engaging a similar pinion a mounted freely on the cen-- eled on the lower portion of said pin, a rear plate Z connecting said top and bottom.

plates and having a large opening through which the central shaft W and its surrounding bushing extend, and a front plate m integrally connecting the top and bottom plates y and 7a and having at the center a spider with a hub 07. which forms a bearing for a short shaft 0 having on its inner end a beveled pinion p in engagement with the beveled pinion g. The lower plate is of the adjustable portion of the head has a downward extension which provides bearings for an intermediate shaft 9 and for the spindle F of the grinding wheel A. The shafts 0, g and F are parallel with each other and provided on their outer ends with engaging gears r, s and t by which the grinding wheel is driven at a high rate of speed from the shaft 0. The projecting gears are covered by a plate u fastened on the front wall m of the adjustable portion of the head.

The gears from pinion g to the grinding wheel are thus adapted to be rotated together about the vertical axis of the central pin a and this axis passes through the center of the thickness of the grinding wheel, as shown in Fig. 3, and throu h the vertical diameter thereof as shown in ig. 5. Consequently as the movable parts are adjusted the point of contact of the grinding wheel A with the work B remains immovable and only the angle of the Wheel to the work is shifted. Fig. 4 is a plan view showing a i suitable angle, the work B and the grinding wheel A being indicated in dotted lines.

- This angle may be adjusted by loosening the bolt '0 which passes through a circular slot to in the fixed top plate X and is fastened in the adjustable top plate j, turning the adjustable portions until the correct angle is secured at which the grinding wheel fits in the groove of the worm to be ground and then clamping the "bolt '0. Fastened to the rear wall of the fixed portion of the head is an arm y curved on a circle about the vertical pin a and bearing against the side of the movable portion of the head to support the both ends to the uniform radius.

feature latter. A further support is provided by an upwardly projecting portion .2 of the front wall of the movable member, which bears against the circular edge of the fixed top X.

The grinding wheel carrier or support, comprising the barrel U and the head E are mounted in a slide or carriage comprising a hub 2 and flange or plate 3 which constitutes in fact the front plate of the upper portion of the machine and is arranged to have a slight vertical movement in guides at the sides of the machine and is provided with adjustable gibs 3*.for maintaining a good sliding fit. This part of the apparatus and the means for adjusting it by hand to feed the cutter to the work and automatically to grind teeth of special shape are similar in design and operation to the carriage and feeding and controlling means described and claimed in my co-pending application for patent for a machine for cutting hobs, worms and the like, No. 87 5654, filed December 5, 1914.

0n the outer end of the barrel U just in the rear'of the head E is a cam 4 which is circular throughout the greater portion of its contour but is provided with a portion 4 of slightly increased radius and of a length corresponding to .the period of time during which the grinding wheel is in engagement with .the work; the portion 4 tapering gradually and symmetrically at through intermediate means hereinafter de scribed. By means of the hand wheel 7 the grlndlng wheel is first raised to permit the insertion of the work piece and is then fed downward to a proper engagement with the work. The carriage may rest directly upon the upper end of the rod 5 or it may be lifted to clear the rod and to bring its weight upon an equalizing lever-8 which is pivoted on the rod 5. The lever is pivotally connected at its rear end to a lug 9 fastened on the lower portion of the hub 2, and carries between the forks of its forward end a hearing roller 10 for the cam 4. The forward end of the hub 2 carries a pair of lugs 11 embracing and guiding the forward arms of the lever. The lever comprises two members and these are'mounted eccentrically on the ends of the pivot pin 12. On one end of this pin is carried a handle or crank 12 which is accessible from the open rear side of the machine and which may be turned to lift or lower the lever relatively to the rod 5. Fig. 6 shows the lever in a lowered position. The carriage restsdirectly on the upper end The cartit -up and the forward arm falls.

imam

of the rod 5 and the cam clears the roller 10 in all positions of the cam. By reversing the position of the handle 12 as indicated by the arrow, Fig. 6, the eccentric pin will lift the lever until the roller 10 bears against the cam in all positions of the latter and holids the carrier clear above the end of the r0 5.

In the illustrated case, the equalizing lever and cam being inoperative, there is a simple circular movement ofthe grinding wheel. With the equalizing lever in its operative position, however, the grinding wheel is given a compound movement. As the higher point of the cam comes to bear on the forward end of the lever 8 the entire carrier slides upward with a parallel movement. The rear arm of the lever is carried Thus there is simultaneously an upward movement of the cam and the parts connected therewith,

including the giinding wheel, and a downward movement of the roller 10 on which the cam rests; so that the net or absolute movement of the grinding wheel is only a portion of the throw of the cam, being one-half where the two arms of the lever 8 are of equal length as in the case illustrated.

This mechanism permits of a Very nice control of the movement of the carrier toward and from the work by utilizing only a fraction of the throw of the cam and simi larly reducing any error in the contour of the cam. The purpose of this movement being to .relieve the ends of the worm threads so that they will enter and leave the grooves in the worm gear which is to be driven thereby, with a minimum amount of shock, the portion of the length of the thread over which the relieving taper extends being comparatively short, and the relief in the width of the thread being extremely slight and being as nearly as possible on a long curve tangent to the central portion of the tooth so as to come gradually to a full bearing against the side of the groove in the driven worm gear; it will be appreciated that a perfectly controlled and nicely graduated movement is of great importance in producing a smoothly running worm. The worm may be first cut with unrelieved ends and the ends then ground down sufliciently in thepresent machine. Preferably, however, the worms are cut with the desired relief and are merely ground to a smooth and perfectly shaped surface in the present machine.

I have illustrated the machine arranged forthe grinding of an ordinary worm. The invention, however, may belapplied to the grinding of various styles of gears such as spiral or skew bevel gears for example; the movement of the grinding wheel bodily and the simultaneous movement of the work at an angle to such bodily movement of the wheel making it feasible to grind teeth of practically any desired inclination to the axis of the work.

The relieving of the ends of the'teeth of a worm or similar curved tooth gear and the method and mechanical movements for doing this are described and claimed broadly in connection with a hobbing or cutting machine in my co-pending application for patent above referred to and are claimed in the present application only in connection with grinding or polishing apparatus.

Though ll have described with great particularity of detail a certain specific embodiment of my invention yet it is not to be understood therefrom that the invention is restricted to the particular embodiment disclosed. Various modifications thereof in detail and in arrangement of the parts may be made by those skilled in the art without departure from the invention as defined in the following claims.

What I claim is- 1. A machine of the class described comprising in combination a grinding wheel, means for rotating it about its central axis, means for rotatingthe work and means for simultaneously rotating the grinding wheel bodily lengthwise of the work so as to cause the wheel to grind an inclined tooth on the work.

2. A machine of the class described comprising in combination a grinding wheel,

means for rotating it about its central axis, means for rotating the work and means for simultaneously moving the grinding wheel bodily in a circular orbit lengthwise of the work so as to cause the wheel to grind an inclined tooth on the work, and means for adjusting the wheel so as to bring its edge into planes corresponding with teeth of different inclinations.

3. A machine of the class described comprising in combination a carrier carrying a grinding wheel, means for rotating the carrier in a direction lengthwise of the work, means for rotating the grinding wheel and means for rotating the work about its lengthwise axis.

4. A machine of the class described comprising in combination a grinding wheel, means for rotating it, means for simultaneously moving it across the work, means for simultaneously moving the work in a direction at an angle to the bodily movement of the wheel so as to cause the latter to grind an inclined tooth on the work and means for I ously moving it across the work, means for simultaneously moving the work in a d1rection at an angle to the bodily movement of the wheel so as to cause the latter to grind an inclined tooth on the Work and means for effecting a relative movement between the wheel and the work automatically through a determined distance during their engagement with each other in a direction to grind a tooth of an automatically determined variation in width at different points in its length.

6. A machine of the class described comprising in combination a carrier carrying a grinding wheel, means for rotating the carrier, and a shaft extending through said carrier and serving to rotate said grinding wheel on its own axis.

7. A machine of the class described comprising in combination means for rotating the work, a carrier carrying a grinding wheel and having an axis angular to tha tlof the work, means for rotating said carrier and mechanism for giving to said carrier a movement toward and from the work automatically at certain points during the engagement of the wheel with the work.

' 8. A machine of the class described comprising in combination means for rotating the work, a carrier carrying a grinding wheel and having an axis angular to that of the work, means for rotating said carrier and mechanism for giving to said carrier a movement toward and from the work automatically at certain points during the engagement of the wheelv with the work, and means for rendering this automatic mechanism inoperative.

9. A machine of the class described comprising in combination "means for rotating the work, a' carrier carrying a grinding wheel and having an axis angular to that of the work, means for rotating said carrier, means for moving said carrier from the work by hand, mechanism for giving to said carrier a movement toward and from the work automaticallyat certain points during the engagement of the wheel with the work.

10. A machine for grinding toothed workpieces including a grinding wheel and mechanism for moving it across the work in such a direction as to grind a tooth of automath cally determined varying width at different points in its length.

11. A machine for grinding toothed workpieces including a grinding wheel and mechanism for moving it across the work in such a direction as to grind a tooth with an automatically determined taper in width at both ends of its length.

12. A machine for grinding toothed workpieces including a grinding wheel and mechanism for moving it across the work in such a direction as to grind a tooth tapered in Width at both ends of its length, said mechanism including a cam for moving the wheel toward and from the work in traversing the length of the tooth.

13. A machine for grinding toothed workpieces including a grinding wheel and mechanism for moving it across the work in such a direction as to grind a tooth of varying width at different points in its length, said mechanism including a cam for moving the wheel toward and from the work and means for utilizing only a fraction of the throw of the cam.

14. A machine of the class described including in combination a grinding wheel, a

rotatable carrier carrying the same, gearing carried also by said carrier and engaging the spindle of said wheel, and an axial shaft in said carrier and engaging said gearing to rotate said wheel.

15. A machine of the'class described including in combination a grinding wheel, a rotatable carrier carrying the same, a shaft extending transversely of the axis of said carrier, saidcarrier being adjustable along said shaft, and means for rotating said carrier from said shaft in all positions of such adjustment. I

16. A machine of the class described including in combination, a grinding wheel, a rotatable carrier carrying the same, gearing carried also by said carrier and engaging the spindle of said wheel, and an axial shaft in said carrier and engaging said gearing to rotate said wheel, said wheel being angularly vadjustable about a line passing substantially diametrically through its cutting edge.

17. A machine of the class described including in combination a grinding wheel, a

tooth and simultaneously effecting a relative movement of such grinding face toward and away from the base of the tooth so as to, grind a tooth of varying width at different;-

points in its length.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

WILLIAM CANNELL.

Witnesses:

THEo. W. ELLIS, ELISHA H. BREWSTER. 

